1. Field of the Invention
The present invention relates to a wired circuit board and, more particularly, to a wired circuit board such as a chip on film (COF) board or a flexible wired circuit board.
2. Description of the Related Art
A wired circuit board such as a COF board or a flexible wired circuit board includes an insulating base layer, a conductive pattern formed thereon, and an insulating cover layer formed on the insulating base layer so as to cover the conductive pattern. Such a wired circuit board is widely used in the field of various electric equipment and electronic equipment.
For such a wired circuit board, it has been proposed to, e.g., emit a light beam toward a wired circuit board, and measure the reflected light or transmitted light thereof so as to sense a foreign matter or the displacement of a conductive pattern or an insulating cover layer, and sense a defect in the wired circuit board (see, e.g., Japanese Unexamined Patent No. 2005-283583).